1. Field of the Invention
This invention relates to urogenital surgery.
2. Description of the Related Art
Female genital prolapse has long plagued women. It is estimated by the U.S. National Center for Health Statistics that 247,000 operations for genital prolapse were performed in 1998. With the increasing age of the U.S. population, these problems will likely assume additional importance.
The common clinical symptoms of vaginal prolapse are related to the fact that, following hysterectomy, the vagina is inappropriately serving the role of a structural layer between intra-abdominal pressure and atmospheric pressure. This pressure differential puts tension on the supporting structures of the vagina, causing a “dragging feeling” where the tissues connect to the pelvic wall or a sacral backache due to traction on the uterosacral ligaments. Exposure of the moist vaginal walls leads to a feeling of perineal wetness and can lead to ulceration of the exposed vaginal wall. Vaginal prolapse may also result in loss of urethral support due to displacement of the normal structural relationship, resulting in stress urinary incontinence. Certain disruptions of the normal structural relationships can result in urinary retention, as well. Stretching of the bladder base is associated with vaginal prolapse and can result in complaints of increased urinary urgency and frequency. Other symptoms, such as anal incontinence and related bowel symptoms, and sexual dysfunction are also frequently seen with vaginal prolapse.
Anterior vaginal wall prolapse causes the vaginal wall to fail to hold the bladder in place. This condition, in which the bladder sags or drops into the vagina, is termed a cystocele. There are two types of cystocele caused by anterior vaginal wall prolapse. Paravaginal defect is caused by weakness in the lateral supports (pubourethral ligaments and attachment of the bladder to the endopelvic fascia); central defect is caused by weakness in the central supports. There may also be a transverse defect, causing cystocele across the vagina.
Posterior vaginal wall prolapse results in descent of the rectum into the vagina, often termed a rectocele, or the presence of small intestine in a hernia sac between the rectum and vagina, called an enterocele. Broadly, there are four types based on suspected etiology. Congenital enteroceles are thought to occur because of failure of fusion or reopening of the fused peritoneal leaves down to the perineal body. Posthysterectomy vault prolapses may be “pulsion” types that are caused by pushing with increased intra-abdominal pressure. They may occur because of failure to reapproximate the superior aspects of the pubocervical fascia and the rectovaginal fascia at the time of surgery. Enteroceles that are associated with cystocele and rectocele may be from “traction” or pulling down of the vaginal vault by the prolapsing organs. Finally, iatrogenic prolapses may occur after a surgical procedure that changes the vaginal axis, such as certain surgical procedures for treatment of incontinence. With regard to rectoceles, low rectoceles may result from disruption of connective tissue supports in the distal posterior vaginal wall, perineal membrane, and perineal body. Mid-vaginal and high rectoceles may result from loss of lateral supports or defects in the rectovaginal septum. High rectoceles may result from loss of apical vaginal supports. Posterior or posthysterectomy enteroceles may accompany rectoceles.
Several factors have been implicated as being involved in genital prolapse in women. It is thought that individual women have differing inherent strength of the relevant connective tissue. Further, loss of connective tissue strength might be associated with damage at childbirth, deterioration with age, poor collagen repair mechanisms, and poor nutrition. Loss of muscle strength might be associated with neuromuscular damage during childbirth, neural damage from chronic straining, and metabolic diseases that affect muscle function. Other factors involved in prolapse include increased loads on the supportive system, as seen in prolonged lifting or chronic coughing from chronic pulmonary disease, or some disturbance in the balance of the structural support of the genital organs. Obesity, constipation, and a history of hysterectomy have also been implicated as possible factors.
As noted, vaginal prolapse and the concomitant anterior cystocele can lead to discomfort, urinary incontinence, and incomplete emptying of the bladder. Posterior vaginal prolapse may additionally cause defecatory problems, such as tenesmus and constipation. Furthermore, apart from the physical symptoms, vaginal prolapse has been shown to result in a lower quality of life for its sufferers, including feeling less attractive, less feminine, and less sexually attractive.
Vaginal prolapse develops when intra-abdominal pressure pushes the vagina outside the body. In a normal situation, the levator ani muscles close the pelvic floor. This results in little force being applied to the fascia and ligaments that support the genital organs. Increases in abdominal pressure, failure of the muscles to keep the pelvic floor closed, and damage to the ligaments and fascia all contribute to the development of prolapse. In addition, if a woman has a hysterectomy, the vaginal angle may be altered, causing increased pressure at a more acute angle, accelerating the prolapse.
There are generally two different types of tissue that make up the supportive structure of the vagina and uterus. First, there are fibrous connective tissues that attach these organs to the pelvic walls (cardinal and uterosacral ligaments; pubocervical and rectovaginal fascia). Second, the levator ani muscles close the pelvic floor so the organs can rest on the muscular shelf thereby provided. It is when damage to the muscles opens the pelvic floor or during the trauma of childbirth that the fascia and ligaments are strained. Breaks in the fascia allow the wall of the vagina or cervix to prolapse downward.
As noted above, the levator ani muscles close the pelvic floor so the organs can rest on the muscular shelf thereby provided. The levator ani muscles arise from the pubis, the pelvic fascia, and the ischial spine. They insert on the pelvic viscera, coccyx, and the fibrous raphe of the perineum.
When damage has occurred in the levator muscle, most commonly as a result of obstetric injury, the anatomical defect is noted as a tendency towards a vertical elongation of the levator plate. This downward sagging of the levator plate results in the longitudinal enlargement of the levator hiatus with secondary placement of the cervix and upper vagina upon the levator hiatus. With increased intra-abdominal pressure the defective levator plate is no longer supportive of the downward movement of the uterus, cervix and upper vagina, which are resting upon the levator hiatus, and genital prolapse develops. Over a period of time elongation of the uterosacral and cardinal ligaments will result.
The cardinal and uterosacral ligaments form a suspensory mechanism that suspends the vaginal apex but allows for some vertical mobility. In the normal woman the cervix will descend to but not below the plane of the ischial spines. Damage to the cardinal uterosacral ligament complex permits the uterus and upper vagina to telescope downwards, like an inverted sock. Complete failure of the cardinal uterosacral ligament complex will result in a “cervix-first” prolapse.
Anteriorly, the continence mechanism is maintained by the integrity of the sub-urethral hammock and the insertion of pubo-urethral ligaments into the mid urethra. Posteriorly, the perineal body needs to be firm and substantial in size to allow stretching and angulation of the vagina around it. Levator muscle distension can have a significant effect on perineal body descent and future pelvic prolapse, as well as prolapse recurrence.
Treatment of vaginal prolapse is uncertain, and generally based on the symptoms of the prolapse. If symptoms are more severe, treatment is commonly by either surgery or pessary. Surgical options might include hysterectomy or by uterus-saving procedures. Such procedures may include abdominal or vaginal access routes. Sacralcolpopexy or sacrospinous fixation may be used. Anterior colporrhaphy is often utilized for treatment of anterior vaginal prolapse. In addition, methods of surgical repair using mesh or biological implants, or a combination thereof, to support the prolapsed organ in its appropriate position, have been developed, and may use either a transobturator or vaginal approach.
Traditional anterior prolapse repairs have a relatively high failure rate. Consequently, mesh or grafts have been used to provide additional support for a traditional repair. However, the typical placement of such augmentation of the levator muscle is through a transvaginal approach, with transvaginal dissection. Such transvaginal dissection can be more difficult for the surgeon and may lead to further failures. Consequently, there is a need for alternative methods and apparatus for augmentative support of repaired levator muscle in cases of pelvic organ prolapse.